The numerical control machining process analysis of the parts is the most important part of the NC program. From the design of the drawings to the qualified delivery of the finished products, it is necessary to consider not only the preparation of the NC program, but also the influence of various problems during processing. So before starting programming, you must analyze the design drawings and technical requirements in detail to get the best processing solution.
First, the original data required for the development of CNC machining route
1. Part design drawings, technical materials, and assembly drawings of the products.
2. Production batch of parts.
3. Relevant technical standards required for CNC machining of parts such as enterprise standards and process documents.
4. Quality standards for product acceptance.
5. Existing production conditions and information. Manufacturing capacity of process equipment and special equipment, specifications and performance of processing equipment and process equipment, and technical level of workers.
Second, the analysis of the blank state
Most part design drawings only define the shape and size of the part when it is machined, and do not specify the data of the original blank material, including the type, size, shape, heat treatment state, and hardness of the wool. When programming, an in-depth understanding of wool is an important starting point. Using this raw information is beneficial to NC programming.
1. Assembly drawing and part drawing analysis of the product
For the analysis and research of assembly drawings, it is mainly familiar with the performance, use and working conditions of the products, clarifying the mutual assembly position and function of the parts in the products, understanding the basis for the formulation of various technical conditions on the parts drawings, and finding out the main technical key points. The problem lays the foundation for a correct processing plan. Of course, when the ordinary parts are subjected to process analysis, the analysis of the assembly drawings may not be performed.
2, the process analysis of the parts drawing
The analysis and research of the parts drawing is mainly to carry out the process review of the parts, such as checking the view of the design drawings, dimensioning, technical requirements, errors, omissions, especially for parts with poor structural structure, if possible and design The personnel communicate or make revisions, and the designer decides whether to make the necessary modifications and improvements.
(1) Analysis of the integrity and correctness of the parts drawing
The view of the part should meet the requirements of national standards, the position is accurate, and the expression is clear; the relationship between geometric elements (points, lines, and faces) (such as tangency, intersection, parallel) should be accurate; the dimension should be complete and clear.
(2) analysis of parts technical requirements
The technical requirements of the parts mainly include dimensional accuracy, shape accuracy, positional accuracy, surface roughness and heat treatment requirements. These technical requirements should be the limit values under the premise of ensuring the performance of the parts. The analysis of the technical requirements of parts is mainly to analyze the rationality of these technical requirements and the possibility of realization, focusing on the processing precision and technical requirements of important surfaces and parts, and preparing for the formulation of reasonable processing plans. At the same time, it is analyzed to determine whether the technical requirements are too strict, because too high precision and too small surface roughness requirements will complicate the process, increase the difficulty of processing, and increase unnecessary costs.
(3) Analysis of dimensioning methods
The dimensioning methods for part drawings include local dispersive labeling, centralized labeling, and coordinate labeling. For the parts machined on the CNC machine, the dimensions on the part drawing should be as concentrated as possible or marked with the same reference (ie, the coordinate size) on the premise of ensuring the performance. This facilitates the NC programming. It also facilitates the unification of design benchmarks, process benchmarks, and programming origins.
(4) Analysis of parts and materials
Under the premise of satisfying the function of the parts, cheap materials should be used. When selecting materials, they should be based on domestic products, and do not easily choose expensive and scarce materials.
(5) Structural process analysis of parts
The structural manufacturability of the part refers to the feasibility and economy of the designed part, which can be manufactured under the premise of meeting the performance requirements. Good structural processability makes parts easy to process, saves costs, and saves materials. Poor structural processability makes processing difficult, increases costs, wastes materials, and even cannot be processed. Through the process of analyzing the structural characteristics, accuracy requirements and complexity of the parts, the machining methods required for the parts and the types and specifications of the CNC machine tools can be determined.